Thimphu Dzongkhag is located in the western central part of Bhutan. The district spans a variety of ecological zones, though the capital city itself rests entirely within a constrained, linear valley carved by the Wang Chhu (also known as the Raidāk River in its lower courses). The river flows north to south, acting as the central spine along which urban development has taken place.
The geography of the district is dominated by dense alpine and temperate forests. The higher elevations in the northern part of the district are characterized by rugged, snow-capped peaks and alpine meadows, while the lower valley floors support broadleaf and coniferous forests. Thimphu is deeply integrated with its natural surroundings, and despite rapid urbanization, the hillsides immediately adjacent to the city remain heavily forested.